<template>
  <div>
     <div class="todo-footer">
        <label>
            <!-- 思路:v-model直接绑定给我们设置的计算属性(计算属性可读可写) -->
          <input type="checkbox" v-model="allIschecked"/>
        </label>
        <span>
          <span>已完成{{checkedNum}}</span> / 全部{{todoList.length}}
        </span>
        <button class="btn btn-danger" @click="deleteAll">清除已完成任务</button>
      </div>
  </div>
</template>

<script>
export default {
name:'Footer',
props:['todoList','checkAllhandle','deleteAll'],
computed:{
   allIschecked:{
     set(value){
        // console.log(value);
        this.checkAllhandle(value)
     },
    get(){
         /* 
        every:返回布尔值，遍历数组,如果每次回调函数都返回true,则every返回true,只要有一个回调返回false,则停止遍历,every返回false
      */
    //  console.log(this.todoList);
     return (
        this.todoList.every((item)=>item.done)&& this.todoList.length!==0
     )
        
     
    }
   },
   checkedNum(){
    return this.todoList.reduce((p,c)=>(c.done?p+1:p),0)
   }
},
}
</script>

<style scoped>
/*footer*/
.todo-footer {
  height: 40px;
  line-height: 40px;
  padding-left: 6px;
  margin-top: 5px;
}

.todo-footer label {
  display: inline-block;
  margin-right: 20px;
  cursor: pointer;
}

.todo-footer label input {
  position: relative;
  top: -1px;
  vertical-align: middle;
  margin-right: 5px;
}

.todo-footer button {
  float: right;
  margin-top: 5px;
}
</style>